Definition

1. Adjective:
   • Corresponding or similar in position, structure, or function: Refers to things that share a fundamental similarity in their arrangement, role, or characteristics, often due to a common origin. This is frequently used in biology and genetics.
   • Derived from an organism of the same species: Specifically in medicine or biology, describing tissues or grafts that originate from a genetically similar or the same type of organism.
   • Having the same evolutionary origin but serving different functions: In evolutionary biology, describing anatomical structures in different species that share a common ancestral origin, even if their current functions differ.

Usage Examples

• Adjective:
  • The scientist studied the homologous chromosomes during cell division.
  • A homologous blood transfusion is generally safer.
  • The flipper of a whale and the human arm are homologous structures, both evolving from a common ancestor's limb.

Advanced Usage

• Homologous recombination: A key genetic process where two similar or identical DNA molecules exchange genetic material.

  • Gene editing often relies on the principle of homologous recombination.

• Homologous series: In chemistry, a series of organic compounds with the same functional group, differing by a constant unit (like CH₂).

  • Alkanes form a homologous series where each member differs by a -CH₂- group.

Variants and Related Words

• Homology (noun): The state of being homologous; the study of such similarities.

  • The homology between the two genes was striking.

• Homolog (noun): One of a pair of homologous chromosomes, or a thing that is homologous to another.

  • Each homolog carries alleles for the same genes.

Synonyms

• Analogous (Note: 'Analogous' typically refers to similarity in function but not necessarily in origin, whereas 'homologous' emphasizes shared origin.)
• Corresponding
• Similar in structure

Antonyms

• Analogous (in the specific context of evolutionary origin, as analogous structures share function but not origin)
• Heterologous (derived from a different species or source; not corresponding)

Adjective

1. corresponding or similar in position or structure or function or characteristics; especially derived from an organism of the same species
   • a homologous tissue graft
2. having the same evolutionary origin but not necessarily the same function
   • the wing of a bat and the arm of a man are homologous